I wrote some code in c, using pthread (I configured the linker and compiler in eclipse IDE first).
Code: #include <pthread.h>
#include "starter.h"
#include "UI.h"
Page* MM;
[Code]....
I have to compute prime numbers with threads in C. So I choose the algorithm "Sieve of Eratosthenes" and I tried to create 2 threads, but I don't know how to optimize my computing function with threads I beg for help. This is my function:
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but it seems like the both of the threads are calculating the same function twice? Is it possible to be optimized or not?
I have faced a problem with my code (a small tcp server). After the thread returns, the memory not decreases, but when a new connection is made, memory not increases and the new connection initialize a new thread with a same thread id of the previous thread. When two connections are made at same time, two thread ids are created and when the respective threads returns the memory not decreases. The Valgrind indicates that not memory leak occurs, the pointers are released. Indeed, more memory are allocate when new thread id is created. i used gcc and debian.
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I have created a pthread, and installed a signal handler inside that, same way as we do in main( ) function. The thread's signal handler is a separate function. Surprisingly, it is not working, that is the thread's signal handler is not able to catch signals. Here is the code:
Code: #include <unistd.h>
#include <sys/types.h>
#include <stdio.h>
#include <signal.h>
typedef struct data
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I have an application that has pretty large memory profile. The general program flow is as follows:
Code:
main:
do 10 times:
[code]....
im writing a cross-platform software (linux/solaris/mac/bsd) so i was wondering, how portable is pthread library? out of 10 linux distros, how many will have it by default? and does it exists on mac/solaris/bsd by default? or user will have to install it?
View 6 Replies View RelatedI want to suspend/resume a thread. The library I am using is pthread.h.I am also running my application on linux.Is there any function in pthread. let me suspend a thread temporary?I have read a document in which it was mentioned thatthread does not support suspend/resume
View 4 Replies View RelatedI'm trying to figure out how pthreads are mapped from the compiler to the Linux kernel. The pthread prototypes are found in a compiler header file (pthread.h), yet the kernel would be responsible for scheduling the threads. So, how does the compiler resolve the pthread symbols at compile time?
View 1 Replies View RelatedI am wondering if pthread could make that a single thread keeps the "mutex" all the time if the time it remains unlocked is very small.
thread1
{
while (1)
{
lock; do_task(); unlock();
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I experiment the thread2 never getting access to the mutex and never printing the nice message. I would expect that once thread2 calls "lock", it would get the mutex as soon as thread1 calls unlock() but it does not seem to be the case. If I add a sleep of some microseconds (100) in thread1 after unlocking the mutex, it solves the problem.
Does anyone know if this behaviour is normal? Is there a way to configure my mutex so that thread2 receives it when unlocked?I use
pthread_mutexattr_settype(&att, PTHREAD_MUTEX_RECURSIVE_NP);
pthread_mutex_init(&handle, &att);
to create my mutex. I am running ubuntu 9.04
I am working on a large program in C to run on Puppy Linux. I have multiple pthreads running. I want to be able to set the pthread SCHED_POLICY and priority in my program but I want a user to be able to run the program without root privilege.
Using a sticky bit and root ownership gives the user too much power because they will be able to write and compile their own scripts. Is there a way to use 'sudo' when I set the thread parameters from my program or something like this?
Code:
#include <iostream>
using namespace std;
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I am doing some Linux kernel programming for my research project. I need to record the timestamp (by using cpuid and rdtsc) when an interrupt handler (top half) is first invoked. Due to the time critical nature of the problem itself, I have to do the timestamping inside the interrupt handler itself (the first operation when the handler is called). However, I understand that tasks that are not so time critical should be deferred to a tasklet function (bottom half) for processing because other interrupts are disabled in a (top-half) interrupt handler. I am currently out of idea on how I can pass the timestamp information that I have obtained in the interrupt handler to the corresponding tasklet function.
View 2 Replies View RelatedI'm building a simple(?) socket server using threads to serve up a few requests. The spec is such that I have to listen to three ports at once, so I decided to use pthread to create three separate threads that would wait for connections, then spawn new threads to handle them.
The problem is that when I do this, for some reason the program never enters the wait loop and instead terminates (All three threads did get created since the messages get printed properly.) It gets to the line which prints "???", but not the line after the accept() call.I don't see an open port when I check for one either so I'm 99% sure they're terminating.Basically I have a main() method which has three calls to pthread_create, which should result in three threads being run that all wait for connections (listenOnPort). After each thread creation I print some info to make sure it's actually being created.
By the way, when I just run listenOnPortwithout threading, the server appears to enter the loop correctly and seems to be waiting for requests. It's only when I run the functions as threads that the problem seems to happen.The source is attached below. Any help will be appreciated. Much of the code is borrowed from a website (I can't post it because I am new here.) You need not worry about the handler_ methods because those are just methods that are run by the threads themselves.
Also--the original source was in C and I changed it to C++. Should I just use C?
server.h Code: /*
* server.h
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i have an application that launches several pthreads, i know that the default size used by Linux is 8Mb for each pthread. However i would like to optimize the total memory usage by my application by decreasing the default stack size of each pthread to the needed resources. My questions:
- Are there any rules to set the pthread stack size.
- How to compute the memory needed by each thread.
- Is the malloc call inside a thread counted from the stack size of the same pthread?
I want to declare a function in a function, but had no success till now, see the error code below and visit the project at sourceforge
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I looked on the net for such function or example and didin't find anything, thus after having made one i guess it would be legitimate to drop it to see what others thinks of it.
#!/bin/bash
addelementtoarray()
{
local arrayname=$1
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I've been trying to understand pthread in C a little better. So I made a simple program that takes in a string from the command line and creates a thread to print the string. I've looked online and copied the basic concepts but there are something things I'm confused about. The programs works just fine, but I have questions. Here's what I have so far.
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One thing I'd like to know is why the 3rd argument in the pthread_create function which is my SendMessage function needs to be typecasted to a void pointer and then send the address of the function. Also as for the 4th argument, I would see typecasting to void pointer in some of the pthread examples I saw online, but in my case I'm passing a char pointer, would this be correct? In which case would I ever want to pass a void pointer?
Do I need a pthread_exit(NULL) in my main and in the SendMessage function? If so, why? I added the sleep() function so that I could let the pthread_exit function in my SendMessage function execute first. I simply saw that the online examples on pthread had pthread_exit() in both locations.
fit a surface i.e. W(x,y) using svdfit() provided by "Numerical Recipes in C". svdfit() is written for curve fitting and not for surface fitting.But one can use svdfit(), as claimed by authors of NR book, to do surface fitting. On page 680 of NR book, authors have given a hint on how to use svdfit() for fitting a surface. But I have not understood it.This link may be helpful (Chapter 15 th is relevant here.):[URL]This is my problem:
Code:
I have a set of 100 numbers. I want to fit a 2-Dimensional function W(x,y) to these numbers.
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I have a question about calling an asm function from C....It doesn't work unless I create an asm variable to hold the value of the function in....Why?Here's the code that doesn't work...
asmfile.s - version one Code: .section .data
mydata: .ascii "this is the message!
.equ mylen, . - mydata
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I want to use backtrace() function to debug a crash issue. I tried this sample code to see how backtrace works. backtrace() function always returns 0 with the below code. Is there any kernel configuration that needs to be set for proper working of backtrace?
#include <execinfo.h>
#include <stdio.h>
#include <stdlib.h>
/* Obtain a backtrace and print it to stdout. */
void
print_trace (void)
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Can you offer me the code about fmod() in C. I want to know how this function work, i am very interested in it because i have no idea to implement it, i want to know... how to write the function... not 'how to use the function' can anyone post the source codes of this function here?
View 6 Replies View Relatedi have an open source application that was developed in C++ (it uses objects and namespaces all over the place). I also have another application that was developed in C. Now i am trying to insert the code made in C into C++ application, but when i do that , i get this error on compilation of the source code:
Code:
error: 'mpi_init_vars' was not declared in this scope the function mpi_init_vars() is not part of object oriented programming and it doesn't belong to any scope, it was compiled into an object file and i am linking it with all objects of C++ application.
How can invoke the C function from C++ object oriented code?
I am trying to build a function inside a script.
Code:
#!/bin/sh
#System commands and other configurable.
IPT=/sbin/iptables
IP6T=/sbin/ip6tables
IPST=/usr/sbin/ipset
MODP=/sbin/modprobe
GET=/usr/bin/wget
INT_NET=192.168.1.0/24 .....
I can find lots of tutorials in how to use if, then, else. However, how do I define a variable inside the function?
SEE>>
Code:
for c in $ISO
Also, am I using the 'test' command correctly( -/+ week as valid test)?
I am doing a web site program and what I need is to call a C program in the PHP cloud.Do u think it would be possible? The web site would get the user input from PHP UI and pass to the C program , the C program would process the function with the user input and output the a PHP page.
View 2 Replies View RelatedI ask if a c++/c function is able to know its name from inside itself:
example:
Code:
int funct1(int a,b)
{
printf("%s ",funct_name());
}
or with a trick.
Code:
#!/bin/ksh
(...)
# FILL UP PARTITION
diskfillerfunction () {
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Test 15: fill up partition /usr/bin/time: cannot run diskfillerfunction: No such file or directory
I am obviously omitting (...) a lot of the code, but the relevant part is all there. How do I 'time' a function?
I wrote a spinner in Perl and when I did a spinner in shell I could just run the subroutine in the background.
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In Perl, how do you run a function in a background and get the PID for that? I know PID in Perl is $$
I know what is the functionality of the sleep() method.
for(i = 0; i < length; i++){
sleep(1000);
printf("%c
", message[i]);
}
Result :every print of the message will be takes 1000sec of gap but i want to know why wee need to use the Sleep function. where exactly it is useful
On this link [URL]4 a return type is defined
Code:
return ((unsigned int)(unsigned long)base & TBASE_DEFERRABLE_FLAG);
What is the above function returning.I am not clear with definition of what is being returned in the above code.
i want to compile function c in java and compile library is success.. when i call the library in java and error is :
Exception in thread "main" java.lang.UnsatisfiedLinkError: no libfunc.so in java.library.path
at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1689)
at java.lang.Runtime.loadLibrary0(Runtime.java:823)
at java.lang.System.loadLibrary(System.java:1028)
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